shoulder to shoulder. >> reporter: at the white house, president obama participated in a moment of silence. late aert the pentagon, he offered hope following a ceremony remembering those killed when a hijacked plane targeted the building. >> no single event can ever change who we are. >> reporter: those same themes of courage rang out near shanksville, pennsylvania, where passengers fought to keep a plane from crashing the capitol. >> we've not forgotten the heroism of your husbands, wives, sons, daughters, mother, fathers. >> reporter: so many fighting for a country they believed in. despite the pain, there are isle signs of healing. this new world trade tower i'm standing in which should be complete in just over a year is a sign to many the city is beginning to move on. danielle leigh. now back to you. >> u.s. troops in kabul, afghanistan, marked the anniversary of the terror attacks at several memorial services. in october of 2001, the u.s. and allies invaded afghanistan. the goal was to oust the taliban regime for sheltering al qaeda leaders who planned the 9/11 attacks. military leade